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BITE STS A. M. ASAY AND J. Il. ASAY, OF PHILADELPHIA, PENNSYLVANIA.

MOLD FOR ARTIFICIAL TEETH.

T o all 'whom it may concern:

Be it known that we, A. M. Asar and J. L. AsAY, both of the city of Philadelphia, State of Pennsylvania, have invented certain new and useful Improvements in Molds for Casting Artificial Teeth; and we do hereby declare the following to be a full, clear, and exact description of the same, reference being had to the accompanying drawing and to the letters of reference marked thereon.

Our invention consists in forming molds for casting artificial teeth substantially as described hereafter, so that depressions of any size or shape may be formed in the bases of teeth during the process of casting, thereby saving the labor incurred in grinding them to the required shape; and our invention further consists in a peculiar construction and arrangement of parts, whereby teeth of any required length of gum may be formed in the same mold.

In order to enable others skilled in the art to make and use our invention we will now proceed to describe its construction and operation.

On reference to the accompanying drawing, which forms a part of this specification, Figure l, is a side view, partly in section, of our improved molds for forming artificial teeth; Fig. 2, a plan view, with the upper portion of the mold removed; Fig. 3, an end View; Fig. 4, detached views of part of our improved molds; Fig. 5, a sectional elevation of part of the molds on line l, 2, Fig. 2; Figs. 6 and 7, sectional views illus- 4trating the different forms of block teeth.

Similar letters refer to similar parts throughout the several views.

A. is the lower portion or base of the mold, in which are cut recesses a, a, of the desired shape for forming the lingual surface of the teeth. This lower portion A of the molds is cut away or recessed at the opposite ends, as seen in Fig. l, for the reception of the blocks B, B, the latter being inclined at the bottom and adapted to the inclination of t-he recesses in which the said blocks canbe slid freely to and fro. From the ends of each recess of the lower portion of the mold, project the rods which passing through the blocks B, B, serve t-he double purpose of guiding the latter, and with the pins t, t, of retaining them in the position to which they have been adjusted.

C, C, (Fig. 4) are `supplementary blocks or plates to be placed (under circumstances alluded to hereafter) between the blocks B and the ends of each recess of the lower portion of the molds, these blocks having holes through which pass the projecting rods 0a,

D is the upperportion or cap of the molds into the under surface of which are cut the depressions for forming the labial, surface of the teeth. This portion D of the mold is beveled on the underside and at the opposite ends, as seen at y, y, Fig. l, and adapted to the beveled tops of the blocks B, which, as seen in the end View Fig. 3, are arched and adapted to the arched undersides of the beveled ends of the upper portion of the mold and this arch is of a shape to correspond to the curve of the block of teeth to be formed in the mold.

Through openings in the pieces B project pins e, 6 the use of which will be more fully explained hereafter.

Supposing that the parts of the mold are in the relative position shown in the drawing. The supplementary' pieces C', C being removed from one end of the mold, the material of which the teeth are to be formed is introduced in a plastic state into the lower mold, over which is fitted the cap D; pressure is then applied until the upper and lower portion of the mold are brought into contact with each other, the material being thus forced into every portion of the mold, while all excess of the material is pressed out at the sides. The pins e are then introduced and pushed forward until their heads come in contact with the end of the block B. After the mold has been subjected to a heat sufficient to evaporate all the moisture from the material, the pins e and t are removed, the pieces B and C slid away, after which the two parts of *the molds A and D can be separated and the completed block of teeth readily removed.

On reference to Figs. l and 2, it will be seen that the pieces B have a rounded projection m, which makes a depression along the whole length of the base of the block of teeth, so that the latter could not be removed from the mold without first drawing away the pieces B. In ordinary molds which are formed of buttwo pieces, it is necessary to make the bases of the blocks of teeth either beveled or slightly curved as seen in Fig. 6 in order that they can be removed. The advantage of the pieces B B. will be apparent lio when it is considered that the' blocks procured at the Wholesale manufacturers are of the form shown in F ig. 6, and that it is necessary to grind away a portion of the block until it assumes the form shown in F ig. 7, an operation requiring nice and tedious manipulation. In extensive establishments for the manufacture of artificial teeth a new mold is required for every different size of block, and in many cases this difference in size is demanded by an increase in or diminution of the length of the gum without any necessity for altering` the shape of the teeth. By sliding back the pieces B, B and introducing the pieces C C blocks of teeth of any required size may be cast from one mold, so far as the length of the gum is concerned, while the recess for fitting over the alveolar process on the plate may be made of any required shape by making the projecting portion m of the piece B of the desired form. After the blocks are taken from the molds in which condition they are very fragile, it is necessary to drill holes perpendicular to the base through which rivets may be passed to secure them to the plate. To prevent the risk of cracking the teeth, incurred by this operation, we form the desired holes by introducing into the material in its plastic state the pins c, e which remain until the block is hard enough to be removed from the mold, when they are withdrawn. This method of lengthening the bases and forming the depressions at the base may be also applied to single teeth as well as those cast in blocks of two or more.

Ve wish it to be understood that we do not claim broadly making a mold in three or more pieces for forming teeth, for this has been done by introducing a third piece to form the grinding surface of molar teeth; neither do we claim forming holes for rivets by introducing pins e while the body is in a plastic state; but i lfVe claim as our invention and desire to secure by Letters Patentl. So constructing molds for articial teeth that by the use of movable pieces B B vand supplementary pieces C C blocks of teeth of any required depth of gum may be formed in the same mold.

2. The use of a movable piece B with its projection m for the purpose of forming a depression of any required form in the base of the block.

3. The combination of the base A and cap D of the mold with the movable pieces B, supplementary pieces C C, guide rods a2 and pins e the whole being arranged substantially as and for the purpose set forth.

In testimony whereof, we have signed our names to this specilication, in the presence of two subscribing witnesses.

A. MERRITT ASAY. J. LAMBERT ASAY.. Witnesses:

HENRY HowsoN, JOHN THOMPSON. 

